A confirmation popup in JS

Question

I am looking into making a confirmation menu in JavaScript to where it will run a set of code depending if you select yes or no.

Now I want it to happen on the window.onbeforeunload event but only when the individual presses "yes" do I want the rest of the code to work. If they press "no" I want the window.onbeforeunload to be cancelled outright. I am wondering if it is at all possible and how. Here is what I have so far. The reason why I want this is because when I run the script the popup shows up on return but before someone would get to choose to stay or leave. The click(); feature starts up erasing the information. I want the .click(); to start up after someone presses "yes" on the return and only if they press "yes".

var validNavigation = false;

function wireUpEvents() {

var dont_confirm_leave = 0; 
var leave_message = document.getElementById("kioskform:broswerCloseSubmit");
var leave_safari = document.getElementById("kioskform:broswerCloseSafari");
      function goodbye(e) {
       if (!validNavigation) {
function disp_confirm()
{
var leaveMessage=confirm("Are you sure you want to leave")
if (leaveMessage==true)
{          if (dont_confirm_leave!==1) {
        if(!e) e = window.event;
        //for IE
        e.cancelBubble = true;
        e.returnValue = leave_message.click();
        //e.stopPropagation works in Firefox.
        if (e.stopPropagation) {
          e.stopPropagation();
          e.preventDefault();
        }
        //return works for Chrome and Safari
         leave_safari.click();
         return '';

        //add the code to delete the kiosk information here.
        // this is what is to be done.
      }
    }

   else 
{
Alert("Returning to the page.")
}
  }
  window.onbeforeunload=goodbye;

  // Attach the event keypress to exclude the F5 refresh
  jQuery('document').bind('keypress', function(e) {
    if (e.keyCode == 116){
      validNavigation = true;
    }
  });

  // Attach the event click for all links in the page
  jQuery("a").bind("click", function() {
    validNavigation = true;
  });

  // Attach the event submit for all forms in the page
 jQuery("form").bind("submit", function() {
    validNavigation = true;
  });

  // Attach the event click for all inputs in the page
 jQuery("input[type=submit]").bind("click", function() {
    validNavigation = true;
  });

}

// Wire up the events as soon as the DOM tree is ready
jQuery(document).ready(function() {
  wireUpEvents();
});

Answer 1

Why not just use window.confirm?